Insertion device positioning guidance system and method

ABSTRACT

There is provided herein a system and a method for guiding insertion of a gastroenteral tube including: an electromagnetic field generator configured to generate an electromagnetic field covering a treatment area; wherein said electromagnetic field generator is external to the patient; a registration sensor configured to mark anatomic locations on the patient&#39;s torso; a gastroenteral tube comprising a tip sensor configured to sense its position and/or orientation relative to the electromagnetic field generator; and a processing circuitry configured to: calculate an orientation of the subject relative to the field generator based on the anatomic locations marked by the registration sensor, load a predefined anatomic map representing a torso; aligning the map based on the anatomic locations marked by the registration sensor, and showing on the map a path of the gastroenteral tube insertion; wherein the path is generated according to changes in the strength of the electromagnetic field sensed by the tip sensor&#39;s during the insertion of the gastroenteral tube, independent of the subject&#39;s movement and independent of deviations in the position and/or orientation of said field generator.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.16/386,493 filed on Apr. 17, 2019 that claims the benefit of priority ofU.S. Provisional Application No. 62/664,447 filed on Apr. 30, 2018. Thecontents of the above application are incorporated by reference as iffully set forth herein in its entirety.

FIELD OF INVENTION

Embodiments of the disclosure relate to insertion device positioningguidance systems and methods,

BACKGROUND OF THE INVENTION

Enteral feeding is often used as nutritional support in patients unableto be fed otherwise. Although many benefits are associated with earlyinitiation of enteral feeding, misplacement of feeding tubes isrelatively common and can result in patient discomfort andcomplications. Confirming the position of the tube only after it isalready inserted delays the feeding and the initiating of hydration ormedication. Bedside electromagnetic (EM) systems for guided placement ofnasoenteral feeding tubes are available and are utilized by medicalstaff during the procedure to avoid misplacement of feeding tubes. Thereis still a need, however, for reliable real-time tracking systems thatprovide enhanced accuracy for critical tool positioning during medicalprocedures.

The foregoing examples of the related art and limitations relatedtherewith are intended to be illustrative and not exclusive. Otherlimitations of the related art will become apparent to those of skill inthe art upon a reading of the specification and a study of the figures.

SUMMARY OF THE INVENTION

The following embodiments and aspects thereof are described andillustrated in conjunction with systems, tools and methods, which aremeant to be exemplary and illustrative, not limiting in scope.

One of the problems often associated with an insertion of a feeding tubeusing an electromagnetic positioning guidance system, is thatreliability is difficult to obtain in the patient environment, which istypically dynamic. For example, the patient often moves, and the bed ismoved from one place to another. There is thus provided herein anelectromagnetic positioning guidance system reliably operable regardlessof the patient's movement or position and which requires no calibration.

According to some embodiments, there is provided an insertion devicepositioning guidance system comprising: an electromagnetic fieldgenerator configured to generate an electromagnetic field covering atreatment area; wherein said electromagnetic field generator is externalto the patient; a registration sensor configured to mark at least threeanatomic locations on the patient's torso; a gastroenteral tubecomprising a tip sensor configured to sense its location relative to theelectromagnetic field generator; and a processing circuitry configuredto: calculate an orientation of the subject relative to the fieldgenerator based on the three anatomic locations marked by theregistration sensor, load a predefined anatomical map representing atorso; aligning the map based on positions corresponding to or adjacentto the suprasternal notch and an atomic location below the suprasternalnotch, such as, but not limited to, the xiphoid process, based on the atleast three anatomic locations marked by the registration sensor, andshowing on the map a path of the gastroenteral tube insertion; whereinthe path is generated according to changes in the strength of theelectromagnetic field sensed by the tip sensor's during the insertion ofthe gastroenteral tube, while minimizing sensitivity to the subject'smovement and/or deviations in the position and/or orientation of thefield generator.

According to some embodiments, the system further comprises a referencesensor configured to be positioned, within the treatment area, on thesubject's torso, the reference sensor configured to define a referencecoordinate system representing the position and orientation of thesubject's torso relative to the field generator;

In some embodiments, the reference sensor is configured to be positionedon a side of the patient's torso. In some embodiments, the anatomicalmap shows a frontal upper view of the subject essentially parallel tothe patient's posture. In some embodiments, the anatomical map shows aside view of the subject. In some embodiments, the anatomical map showsan axial view of the subject.

In some embodiments, the system further comprises a monitor configuredto display the anatomical map.

According to some embodiments, the term “anatomical map” as disclosedherein, may refer to one or more schematic maps, one or more 2Danatomical maps, one or more 3D anatomical maps, or any combinationthereof. According to some embodiments, the term “anatomical map” asdisclosed herein, may refer to a group of maps (e.g., 2, 3, 4 or more),each representing a different view (for example, frontal view, frontalupper view, side view, axial view).

In some embodiments, the registration sensor is a stylus configured tobe manually operated. In some embodiments, the stylus comprises a 5DOFsensor at its distal end.

In some embodiments, the insertion device is a gastroenteral tube.

In some embodiments, the at least three anatomic locations marked by theregistration sensor comprise the xiphoid process and an area inproximity to the left and right claviculae. In some embodiments, the atleast three anatomic locations marked by the registration sensorcomprise the xiphoid process and an area in proximity to the left andright shoulder.

In some embodiments, the determining/estimating the orientation of thesubject comprises defining a first vector between the xiphoid processand the left clavicula and a second vector between the xiphoid processand the right clavicula.

In some embodiments, the position of the suprasternal notch iscalculated based on the marked left and right claviculae.

In some embodiments, the registration sensor is configured to mark atleast four anatomic location, wherein the fourth anatomic locationcomprises the patient's suprasternal notch.

In some embodiments, the at least four anatomic locations include thesuprasternal notch, and the xiphoid process. In some embodiments, afrontal view display of the path of the gastroenteral tube relative tothe suprasternal notch and xiphoid process is indicative of successfulinsertion. In some embodiments, the location where the displayed path(in frontal view) of the gastroenteral tube crosses an axis between thesuprasternal notch and xiphoid process is indicative of a successfulinsertion. In some embodiments, the actual shape of the displayed pathof the gastroenteral tube is indicative of a successful insertion.

According to some embodiments, the processing circuitry may beconfigured to determine/calculate/draw, within the coordinate system, afirst vector (v1) extending between the xiphoid process and the leftclavicula and a second vector (v2) extending between the xiphoid processand the right clavicula, based on the registration of the xiphoidprocess and the left and right claviculae by the registration sensor.According to some embodiments, the processing circuitry may beconfigured to determine/calculate/draw a third vector (v3) based on thefirst and second vectors (v1 and v2), such as the cross product of v1with v2, the third vector being indicative of the position, orientationand/or posture of the subject.

According to some embodiments, the system is configured to determine thepath of the gastroenteral insertion tube without utilizing additionalsensors.

According to some embodiments, there is provided a method for guiding aninsertion device, the method comprising: utilizing an externalelectromagnetic field generator, applying an electromagnetic fieldcovering a treatment area; utilizing a registration sensor, marking atleast three anatomic locations on the subject's torso; and utilizing aprocessing circuitry to: calculate an orientation of the subjectrelative to the field generator based on the three anatomic locationsmarked by the registration sensor, load a predefined anatomical maprepresenting a torso; aligning the map based on positions correspondingto the suprasternal notch or an area in proximity thereof and ananatomic location below the suprasternal notch, such as, but not limitedto, the xiphoid process or the navel, based on the at least threeanatomic locations marked by the registration sensor, inserting agastroenteral tube into the patient, the gastroenteral tube comprising atip sensor configured to sense its location relative to theelectromagnetic field generator; and showing on the map a path of thegastroenteral tube insertion; wherein the path is generated according tochanges in the strength of the electromagnetic field sensed by the tipsensor's during the insertion of the gastroenteral tube, independent ofthe subject's movement and independent of deviations in the positionand/or orientation of said field generator.

In some embodiments, the at least three anatomic locations marked by theregistration sensor comprise the xiphoid process and the left and rightclaviculae.

In some embodiments, the determining/estimating the orientation of thesubject comprises defining a first vector between the xiphoid processand the left clavicula and a second vector between the xiphoid processand the right clavicula.

In some embodiments, the position of the suprasternal notch iscalculated based on the marked left and right claviculae.

In some embodiments, the registration sensor is configured to mark atleast four anatomic locations, wherein the fourth anatomic locationcomprises the patient's suprasternal notch.

According to some embodiments, calculating a position, orientationand/or posture of the subject may includedetermining/calculating/drawing within the coordinate system, a firstvector (v1) extending between the xiphoid process and the left claviculaand a second vector (v2) extending between the xiphoid process and theright clavicula, based on the registration of the xiphoid process andthe left and right claviculae by the registration sensor. According tosome embodiments, the processing circuitry may be configured todetermine/calculate/draw a third vector (v3) based on the first andsecond vectors (v1 and v2), for example by calculating the cross-productof v1 with v2, the third vector being indicative of the position,orientation and/or posture of the subject.

In some embodiments, the method further comprises the step of displayingthe path of the distal tip section of the insertion device on theanatomical map and thus facilitates determination of a successfulmedical procedure.

In some embodiments, the positioning of the reference sensor comprisespositioning thereof on a side of the patient's torso.

In some embodiments, the registration sensor is a manually operatedstylus.

In some embodiments, the anatomical map shows a frontal upper view ofthe subject. In some embodiments, the anatomical map shows a side viewof the subject. In some embodiments, the anatomical map shows an axialview of the subject.

In some embodiments, a path-display of the gastroenteral tube relativeto the first and second anatomic locations is indicative of a successfulinsertion. In some embodiments, the location where the displayed path ofthe gastroenteral tube crosses an axis between the first and secondanatomic locations is indicative of a successful insertion. In someembodiments, the shape of the displayed path of the gastroenteral tubeis indicative of a successful insertion.

In some embodiments, the electromagnetic field generator is not in anyphysical contact with the patient. In some embodiments, theelectromagnetic field generator is designed not to be in physicalcontact with the patient.

In some embodiments, the processor/processing circuity may include twounits or two sub-units. The first is configured to control the entiretracking system (e.g., operate the field generator, read signalsobtained from the registration sensor and optionally also the referencesensor, and calculate a position and orientation thereof relative to thefield generator). The second is configured to receive the calculatedposition and orientation information from the first processor, and usethis information to generate an anatomical map representing the torso ofthe subject and at least the first and second anatomic locations, and toallow visualization on the anatomical map of a position, orientationand/or path of a tip sensor with respect to the first and secondanatomic locations, independent of the subject's movement andindependent of deviations in the position and/or orientation of thefield generator.

According to some embodiments, the tip sensor is positioned at oradjacent to the distal end of the tube/catheter/stylet and aids indetermining the position and orientation of the distal end of thetube/catheter/stylet in a patient.

According to some embodiments, the path of the gastroenteral insertiontube may be determined without utilizing additional sensors.

According to some embodiments, there is provided an insertion devicepositioning guidance system comprising: an electromagnetic fieldgenerator configured to generate an electromagnetic field covering atreatment area; the electromagnetic field generator being external tothe patient; a registration sensor configured to mark a suprasternalnotch and a xiphoid process on the patient's torso; a gastroenteral tubecomprising a tip sensor configured to sense its location relative to theelectromagnetic field generator; and a processing circuitry configuredto: calculate an orientation of the subject relative to the fieldgenerator based on the suprasternal notch and the xiphoid process markedby the registration sensor, wherein calculating the orientationcomprises determining and optionally correcting an angle of theregistration sensor relative to the patient's torso; load a predefinedanatomical map representing a torso; aligning the map based on themarked suprasternal notch and xiphoid process, and showing on the map apath of the gastroenteral tube insertion; wherein the path is generatedaccording to changes in the strength of the electromagnetic field sensedby the tip sensor's during the insertion of the gastroenteral tube,while minimizing sensitivity to the subject's movement and/or deviationsin the position and/or orientation of the field generator.

According to some embodiments, the system is configured to determine thepath of the gastroenteral insertion tube without utilizing additionalsensors

According to some embodiments, the system further comprises a referencesensor configured to be positioned, within the treatment area, on thesubject's torso, the reference sensor configured to define a referencecoordinate system representing the position and orientation of thesubject's torso relative to the field generator;

In some embodiments, the reference sensor is configured to be positionedon a side of the patient's torso.

In some embodiments, the anatomical map shows a frontal upper view ofthe subject essentially parallel to the patient's posture. In someembodiments, the anatomical map shows a side view of the subject. Insome embodiments, the anatomical map shows an axial view of the subject.

In some embodiments, the system further comprises a monitor configuredto display the anatomical map.

According to some embodiments, the term “anatomical map” as disclosedherein, may refer to one or more schematic maps, one or more 2Danatomical maps, one or more 3D anatomical maps, or any combinationthereof. According to some embodiments, the term “anatomical map” asdisclosed herein, may refer to a group of maps (e.g., 2, 3, 4 or more),each representing a different view (for example, frontal view, frontalupper view, side view, axial view).

In some embodiments, the registration sensor is a stylus configured tobe manually operated. In some embodiments, the stylus may include a 5DOFsensor at its distal end.

The systems and methods described herein may be applied, according tosome embodiments, using sensors (e.g., position sensors) such asmagnetic field sensors, impedance-based sensors or ultrasonic sensors.According to some embodiments, the position sensor (e.g., tip sensor)may refer to an element mounted on a catheter/tube/stylet, which causesthe processing circuitry to receive signals indicative of thecoordinates of the element. The position sensor may include a receiver,which generates a position signal to a processing circuitry/control unitbased on energy received by the sensor (for example, from the fieldgenerator). According to some embodiments, the communication between thesensors and the processing unit may be wireless.

More details and features of the current invention and its embodimentsmay be found in the description and the attached drawings.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the present invention, suitable methods andmaterials are described below. In case of conflict, the patentspecification, including definitions, will control. In addition, thematerials, methods, and examples are illustrative only and not intendedto be limiting.

BRIEF DESCRIPTION OF THE FIGURES

Exemplary embodiments are illustrated in referenced figures. Dimensionsof components and features shown in the figures are generally chosen forconvenience and clarity of presentation and are not necessarily shown toscale. The figures are listed below.

FIG. 1 is a block diagram of an insertion device positioning guidancesystem, in accordance with some embodiments;

FIG. 2A schematically illustrates an insertion device positioningguidance system in a hospital setting, in accordance with someembodiments;

FIG. 2B shows an enlarged portion of the illustration of FIG. 2A, inaccordance with some embodiments;

FIG. 2C shows a side view of the illustration of FIG. 2A, in accordancewith some embodiments;

FIG. 2D-2E schematically illustrate an insertion device positioningguidance system in a hospital setting, showing anatomic locations markedusing a stylus, and a reference sensor;

FIG. 3A shows a view of a “live” display of placement of an insertiondevice, in accordance with some embodiments;

FIG. 3B shows a view of a “playback” display of placement of aninsertion device, in accordance with some embodiments; and

FIG. 4 is a flow chart of the steps of a method for guiding the positionof an insertion medical device, in accordance with some embodiments;

FIG. 5 schematically shows vectors utilized for calculating an angle ofa registration sensor utilized for marking of the suprasternal notch andthe xiphoid process on a subject's torso and the subject's torso;

FIG. 6A and FIG. 6B schematically shows left right correction of aninsertion path based on the angle calculated as described with regardsto FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein is a system and method for guiding insertion of aninsertable medical device (e.g., a tube, such as a feeding tube). Thedisclosed system may be used as an insertion device positioning guidancesystem. The system may be used to track and indicate, in real time, thelocation of an insertion medical device during the insertion process. Asone example, the system may track and indicate the location of a tip ofa feeding tube as it is being inserted into the body of a subject.Advantageously, this makes the insertion procedure considerably easierand safer, ensuring that the tube is inserted at a correct location.

According to some embodiments, there is provided an insertion devicepositioning guidance system comprising: an electromagnetic fieldgenerator configured to generate an electromagnetic field covering atreatment area; a reference sensor configured to be positioned, withinthe treatment area, on the subject's torso, the reference sensor isconfigured to define a reference coordinate system representing theposition and orientation of the subject's torso relative to said fieldgenerator; a registration sensor configured to mark at least fouranatomic locations relative to the reference coordinate system; andprocessing circuitry configured to operate said field generator, readsignals obtained from said reference sensor and said registrationsensor, calculate a position and orientation thereof relative to saidfield generator, generate an anatomical map representing the torso ofthe subject and at least a first and a second of the at least fouranatomic locations, said processor/processing circuitry is furtherconfigured to facilitate visualization on the anatomical map of aposition, orientation and path of a tip sensor, located in a distal tipsection of the insertion device, with respect to the first and secondanatomic locations, independent of the subject's movement andindependent of deviations in the position and/or orientation of saidfield generator, thus determination of a successful medical procedure isfacilitated. Optionally, the system further includes a monitorconfigured to display the map.

A reference coordinate system representing the position and orientationof the subject's torso relative to the field generator may be indicatedby a reference sensor configured to be positioned, within the treatmentarea, on a subject's torso. The reference sensor may be positioned on aside of the patient's torso, such that the anatomical map furtherdepicts a body contour of the subject.

The first and the second anatomic locations may be indicated by aregistration sensor configured to mark at least the first and the secondanatomic locations relative to the reference coordinate system.Optionally, the registration sensor is a stylus configured to bemanually operated. Optionally, the first anatomic location is thesuprasternal notch and the second anatomic location is the xiphoidprocess, and a path display of the gastroenteral tube relative to thefirst and second anatomic locations is indicative of a successfulinsertion.

The third and fourth anatomic locations may be the left and rightclaviculae. According to some embodiments, the left and right claviculaealong with the xiphoid process may be used for calculating a position,orientation and/or posture of the subject. According to someembodiments, calculating a position, orientation and/or posture of thesubject may include determining/calculating/drawing within thecoordinate system, a first vector (v1) extending between the xiphoidprocess and the left clavicula and a second vector (v2) extendingbetween the xiphoid process and the right clavicula, based on theregistration of the xiphoid process and the left and right claviculae bythe registration sensor. According to some embodiments, the processingcircuitry may be configured to determine/calculate/draw a third vector(v3) based on the first and second vectors (v1 and v2), for example bycalculating the cross product of v1 with v2, the third vector beingindicative of the position, orientation and/or posture of the subject.

The electromagnetic field generator may be static throughout a durationof a procedure for placing a tube within a body of a subject. In suchcases, a region covered by the electromagnetic field is static/constantthroughout the duration of a procedure for placing a tube within a bodyof a subject. Advantageously, the static electromagnetic field maycontribute to the accuracy of the display.

The anatomical map may show a frontal upper view of the subject and/or aside view of the subject and/or an axial view of the subject.

One example of hardware suitable for use as the abovementionedelectromagnetic tracking system, including the electromagnetic fieldgenerator and one or more of the sensors, is the Aurora® system byNorthern Digital Inc., of Ontario, Canada.

Throughout the following description, similar elements of differentembodiments of the device are referenced by element numbers differing byinteger multiples of 100. For example, an electromagnetic fieldgenerator of FIG. 1 is referenced by the number 102, and anelectromagnetic field generator of FIG. 2, which corresponds toelectromagnetic field generator 102 of FIG. 1, is referenced by thenumber 202.

Reference is now made to FIG. 1 which is a block diagram of an insertiondevice positioning guidance system 100. System 100 includes anelectromagnetic field generator 102 configured to generate anelectromagnetic field 103 a covering at least a region of interest 103 b(e.g., a treatment area such as a patient's torso), a plurality ofelectromagnetic sensors, such as sensors 104 and 106, to indicate aposition of a tip sensor (located in a distal tip section of theinsertion device) on an anatomical map (FIG. 3A-3B) of the region ofinterest 103 b (typically the subject's torso). System 100 furtherincludes a processor 110 configured to operate said field generator,read signals obtained from sensors 104 and 106, and to generate ananatomical map representing the torso of the subject. Processor 110 isconfigured to facilitate visualization on the anatomical map of aposition and path of the tip sensor, on the map, independent of thesubject's movement and independent of deviations in the position and/ororientation of field generator 102. System 100 further includes amonitor 112 operatively connected to processor 110 and configured todisplay, on the anatomical map, the positions of and/or the path of theinsertion device tip during its insertion. In some embodiments, monitor112 may be integrated with processor 110, such as in the case of anall-in-one computer. A determination of a successful medical procedure(for example, an insertion of a feeding tube to the stomach as opposedto the lungs) is thus possible.

Sensor 104 is typically a reference sensor configured to be positionedon a subject's torso. Reference sensor 104 is configured to define areference coordinate system representing the position and orientation ofthe subject's torso relative to the field generator. Optionally,reference sensor 104 may be attached to the skin of the patient, forexample on the side of a patient's torso such as beneath the patient'sarmpit. In such cases, the anatomical map further depicts a body contourof the subject. Reference sensor 104 may be, for example, a 6-DOFelectromagnetic sensor, capable of determining 6 axes of its location(XYZ axes) and attitude (roll, yaw, and pitch) with respect to fieldgenerator 102.

Sensor 106 is typically a registration sensor configured to bepositioned on and/or to mark at least four anatomic (thoracic) locationsover the subject's body (e.g. the subject's torso). Different anatomicallocations may be marked depending on the type of procedure used, thetype of insertion medical device, etc. The marking of the anatomiclocation may be physical, such as attaching a marker/fiducial (such as asticker). Alternatively, the marking of the anatomic location may bevirtual, such as registering a virtual marker/fiducial. The marking, inaccordance with embodiments, may facilitate identification ordesignation of an anatomical location within or on a subject's body suchas, in a non-limiting example, a subject's suprasternal notch, and asubject's xiphoid process.

Optionally, registration sensor 106 is a stylus sensor having a 3 DOFsensor on its distal tip, the stylus configured to be manually operatedto mark at least three anatomic location over the subject's bodyidentified by the operator of the stylus. The marking may be made,merely as an example, by indicating to the software (for example, butnot limited to) by pressing a GUI button or voice activation) oncestylus sensor 106 is positioned over the desired point on the patient'sbody. The marking may be communicated to and registered by processor110.

System 100 is configured to work in conjunction with an insertionmedical device (not shown), such as a feeding tube. The insertionmedical device may include one or more sensors to allow its trackingwithin region of interest 103 b. Preferably, the sensor is located atthe tip of the insertion medical device. In such case, processor 110 andmonitor 112 are configured to compute and display position and/oradvancement of the tip of the insertion medical device between thedesignated anatomical locations leading to the insertion site/targetarea.

According to some embodiments, as used herein the terms “insertiondevice” and “insertion medical device” may refer to any device/tooladapted for insertion into a body. The insertion device may be anymedical insertion device or a medical surgical device. Non-limitingexamples of insertion medical devices include, feeding tubes, such asgastroenteral tubes (for example, nasoenteral feeding tubes),endotracheal tube, tracheostomy tube, stomach tube, catheter tubes orcricothyrotomy tube. Other examples of insertion devices are well knownin the art.

According to some embodiments, the terms “processing circuitry” and“processor” may be used interchangeably.

In some embodiments, the insertion device is a tube. In someembodiments, the tube is a feeding tube. In some embodiments, the tubeis a gastro/enteral feeding tube, such as, but not limited to, anasogastric feeding tube or a nasoenteral feeding tube. According tosome embodiments, the feeding tube may have disposed therein and/orthereon an electromagnetic sensor, for example at its distal end.

Reference is now made to FIG. 2A-2E which schematically illustrate aninsertion device positioning guidance system 200 in a hospital setting,in accordance with some embodiments. FIG. 2A schematically illustratesan insertion device positioning guidance system in a hospital setting,in accordance with some embodiments, FIG. 2B shows an enlarged portionof the illustration of FIG. 2A, in accordance with some embodiments,FIG. 2C shows a side view of the illustration of FIG. 2A, in accordancewith some embodiments and FIG. 2D-2E schematically illustrate aninsertion device positioning guidance system in a hospital setting,showing anatomic locations marked using a stylus, reference sensor (asshown in FIG. 2A-2C) located at different locations, in accordance withsome embodiments.

Similar to system 100 of FIG. 1, system 200 includes an electromagneticfield generator 202. System 200 is configured to work in conjunctionwith an insertion medical device (not shown) which may include one ormore electromagnetic sensors configured to sense and/or interfere withthe electromagnetic field generated by field generator 202. Optionally,monitor 212 of system 200 is integrated with a computer, whichcorresponds to or includes processor 110 of FIG. 1.

According to some embodiments, electromagnetic field generator 202 maybe positioned at such angle and position with respect to the patient, asto enable the generated electromagnetic field to cover the external andinternal working area, or in other words, the entire upper torso (atleast from the nose area to the duodenum area). System 200 furtherincludes a reference sensor 204, and stylus sensor 206 configured to becovered by the field produced by field generator 202, when in use. Thetip sensor of the feeding tube is configured to move inside thedigestive system, and its path can thus be traced. Reference sensor 204may be attached to and/or on the skin of the patient, for examplebeneath the patient's armpit. Suitable means for attachment of thesensor are well known in the art such as, for example, stickers, medicalglue and the like. Reference sensor 204 may serve to detect location(XYZ axes) and attitude (roll, yaw, and pitch) of the patient withrespect to field generator 202, based on the electromagnetic field (notshown) emitted by field generator 202.

Stylus sensor 206 may be manually operated to mark at least threeanatomic locations over the patient's skin. For example, FIG. 2D andFIG. 2E show the marking of four such anatomic locations (indicated as206 a, 206 b, 206 c and 206 d in these figures) on the patient's chest.Anatomic location 206 a is marked over the suprasternal notch, anatomiclocation 206 b is marked over the xiphoid process and anatomic locations206 c and 206 d are marked in the area of the left and right claviculae,respectively. The marking may be communicated to and registered by thecomputer.

Alternatively, only three anatomic locations may be marked, namelyanatomic location 206 b marking the xiphoid process and anatomiclocations 206 c and 206 d marking the left and right claviculae. Theposition of suprasternal notch 206 a may then be calculated fromanatomic locations 206 c and 206 d (e.g., as their mid-point).

Optionally, the computer receives signals from reference sensor 204, andoptionally also from registration sensor 206 and then aligns ananatomical map representative of the subject's torso according to themarked anatomic locations and the signal of the registration sensor;thereafter the medical procedure can begin. In the exemplary case ofguiding the insertion of a feeding tube, the tip of the feeding tube isequipped with a sensor. Optionally, the computer receives the actualposition and orientation of the sensors from a second processor thatreceives the signals and calculates the sensors' locations. Optionally,the computer receives the actual position and orientation from a secondprocessor that receives the signals from the sensors and calculatestheir physical location.

System 200 is operated as follows:

The electromagnetic field generator 202 is activated to apply anelectromagnetic field to the treatment area, covering the subject'storso;

Reference sensor 204 is positioned within the treatment area, on asubject's torso, preferably on the side of the torso. Reference sensor204 defines a reference coordinate system representing the position andorientation of the subject's torso relative to the field generator;

Registration sensor 206 is used to mark at least three anatomiclocations on the subject's torso, preferably including the suprasternalnotch, the xiphoid process and the left and right claviculae;

Utilizing a processor, aligning an anatomical map representing the torsoto the at anatomic locations, e.g. 206 a and 206 b derived from the atleast three anatomic locations marked by registration sensor 206 anddisplaying on monitor 212 the anatomical map and the position and pathof the tip sensor (of the feeding tube). The path of the tip sensor maybe displayed with respect to anatomic locations 206 a and 206 b and/orwith respect to a longitudinal axis passing between anatomic locations206 a and 206 b and along the center of the torso.

Reference is now made to FIG. 3A, which shows a view of a “live” displayof placement of an insertion device, in accordance with some embodimentsand to FIG. 3B, which shows a view of a “playback” display of placementof an insertion device, in accordance with some embodiments. Suchdisplays may be presented on a monitor such as monitor 212. The leftcorner includes general information and patient's details, and in thedisplay of FIG. 3B, also playback controls.

The tip's path is schematically drawn, enabling the caregiver tovisualize the entire insertion path of the tube, until it reaches thedesired location. Optionally, and as shown in FIG. 3A and FIG. 3B, anarrow is near the tip of the path, indicating the actual direction towhich the tube is pointing. Such arrow(s) may help the user to properlyinsert the tube (or better understand where and to which direction thetube is moving). The displays of both FIG. 3A and FIG. 3B show threeviews of the patient's body: a frontal view shown at the top right sideof the monitor, a lateral view shown at the bottom left side of themonitor, and an axial view shown at the bottom right side of themonitor. In some embodiments, different and/or additional views may beshown.

The caregiver inserting the insertion medical device can view theindications on monitor 212 while manually maneuvering the insertion tubeinto the patient's body, so as to guide it to the desired location inthe body.

Reference is now made to FIG. 4, which is a flow chart of the steps of amethod for guiding the position of an insertion medical device, inaccordance with some embodiments. Step 420 includes application of anelectromagnetic field to a treatment area. Optionally, anelectromagnetic field generator, such as electromagnetic field generator202 of FIG. 2, is positioned such that the electromagnetic field coversthe treatment area. Optionally, a reference sensor, such as referencesensor 204 of FIG. 2A-2D, is positioned on a patient within thetreatment area, on a subject's torso, the reference sensor configured todefine a reference coordinate system representing the position andorientation of the subject's torso relative to the field generator (step422). Optionally, the reference sensor is positioned on a side of thepatient's torso such as to indicate a body contour/width of the subject.At least three anatomic locations are marked by utilizing a registrationsensor (step 424). Optionally, a stylus sensor, such as stylus sensor206 of FIG. 2A-2D may be used, the stylus configured to be manuallyoperated to mark the anatomic locations (e.g., anatomic locations 206a-206 d). Alternatively, one or more registration sensors may bepositioned over the at least three anatomic locations (option notshown). Optionally, the first anatomic location is the suprasternalnotch, the second anatomic location is the xiphoid process and the thirdand fourth anatomic locations are the left and right claviculae,respectively. According to some embodiments, the position of thesuprasternal notch may be calculated from the marked left and rightclaviculae (e.g. the mid-point therebetween). Each of steps 420, 422 and424, may be performed simultaneously or in an interchangeable order. Ananatomical map representative of the subject's torso may then be alignedto correspond to the marked anatomic locations and optionally to thesignals obtained from the reference sensor (step 426). A position andorientation of a tip sensor of the insertion device may then bedisplayed on the anatomical map, with respect to the first and secondanatomic locations, independent of the subject's movement andindependent of deviations in the position and/or orientation of thefield generator (step 428). This can be accomplished when all sensorsremain within the sensing volume of the field generator.

Optionally, the anatomical map shows a frontal upper view of thesubject, a side view of the subject, and an axial view of the subject.Optionally, the anatomical map enables visualization of the location ofan insertion device (having an electromagnetic sensor configured tosense and/or interfere with the electromagnetic field generated by thefield generator) within a subject's body by computing and displaying aposition of the inserted device vis-à-vis at least first and secondanatomic locations 206 a and 206 b. Optionally, the computing mayinclude normalizing the position based signals received from referencesensor 204 and/or anatomic location 206 c and 206 d marked byregistration sensor 206, optionally obtained continuously and/or inreal-time during the procedure.

Reference is now made to FIG. 5 which schematically illustrate vectorsutilized for calculating an angle of a registration sensor (stylus),utilized for marking of the suprasternal notch and the xiphoid processon a subject's torso, and the subject's torso.

It is understood that if the registration sensor is perpendicular to thesubject's torso, the orientation (head-leg and left-right) of thesubject may be determined directly by the registration sensor's angle.However, if the registration sensor is tilted towards the subject'shead, legs, left or right, the angle of the registration may bedetermined and corrected.

The calculating of the angle is founded on two preliminary assumptions:

-   -   1. The line connecting the marked points A and B is aligned with        the head-legs axis {right arrow over (AE)}.    -   2. The angle α between {right arrow over (AB)} and the patient        back is predefined (17°).

Based on these assumptions, the up-vector can be calculated andcorrected as follows:

{right arrow over (BC)} represents the direction of the registrationsensor and {right arrow over (BD)} the vector perpendicular to the planecreated from {right arrow over (BA)} and {right arrow over (BC)}. {rightarrow over (BC)} is then around axis {right arrow over (BD)} (to get{right arrow over (BC′)}) so that the angle between the patient's backplane and AB is α, thereby obtaining a corrected up-vector.

After calculating the up-vector, it may still be tilted to one of thesides (left or right).

Such left-right tilting may be corrected by the user after the placementof the gastroenteral tube has been commenced and enough 3D path datapoints have been collected (up to some point between the points A andB). Since the user expects that in the frontal view, the path betweenthe data points be vertical (as the esophagus is going straight down,parallel to {right arrow over (AE)}), the user can choose to “realign”the path if the line obtained is not straight as seen in FIG. 6 a.

In that case, the processing circuitry may be configured to iterate ondifferent angles around the {right arrow over (AB)} axis, and torecalculate the path to minimize the angle between {right arrow over(AB)} and the regenerated path (so that the angle that makes the frontalpath is vertical as possible). Once minimized (for example usinggradient descent technique), an up-vector corrected in all directions(head-leg, right-left) is obtained is illustrated in FIG. 6 b.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device havinginstructions recorded thereon, and any suitable combination of theforegoing. A computer readable storage medium, as used herein, is not tobe construed as being transitory signals per se, such as radio waves orother freely propagating electromagnetic waves, electromagnetic wavespropagating through a waveguide or other transmission media (e.g., lightpulses passing through a fiber-optic cable), or electrical signalstransmitted through a wire. Rather, the computer readable storage mediumis a non-transient (i.e., not-volatile) medium.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Java, Smalltalk, C++ or the like,and conventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general-purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

What is claimed is:
 1. A gastroenteral tube positioning guidance systemcomprising: an electromagnetic field generator; a stylus configured tomark at least three anatomic locations on the patient's torso; whereinthe at least three anatomic locations comprise a xiphoid process andleft and right claviculae of the patient; a gastroenteral tube; a sensorconfigured produce a signal indicative of a strength of theelectromagnetic field and/or changes therein; and a processing circuitryconfigured to: calculate an orientation of the subject relative to theelectromagnetic field, based on the three anatomic locations marked bythe stylus, load an anatomical map representing a torso, align the mapbased on positions corresponding to two locations on the subject's upperbody derived from the at least three anatomic locations marked by thestylus, and show on the map a path of the gastroenteral tube insertion;wherein the path is generated based on the signals produced by thesensor during the insertion of the gastroenteral tube.
 2. The system ofclaim 1, wherein the derived locations are the suprasternal notch andthe xiphoid process.
 3. The system of claim 1, further comprising areference sensor comprising a 6-DOF electromagnetic sensor configured tobe positioned, within the treatment area, on the subject's torso, and todefine the reference coordinate system representing the position andorientation of the subject's torso relative to said electromagneticfield.
 4. The system of claim 1, wherein the anatomical map shows afrontal upper view of the subject, a side view of the subject and/or anaxial view of the subject.
 5. The system of claim 1, further comprisinga monitor configured to display the map.
 6. The system of claims 1,wherein said at least three anatomic locations marked by the styluscomprise the xiphoid process and the left and right claviculae.
 7. Thesystem of claim 6, wherein determining/estimating the orientation of thesubject comprises defining a first vector between the xiphoid processand the left clavicula and a second vector between the xiphoid processand the right clavicula.
 8. The system of claim 7, wherein the positionof the suprasternal notch is calculated based on the marked left andright claviculae.
 9. The system of claim 1, wherein the stylus isconfigured to mark at least four anatomic location, wherein the fourthanatomic location comprises the patient's suprasternal notch.
 10. Amethod for guiding insertion of a gastroenteral tube into a subject, themethod comprising: applying an electromagnetic field covering atreatment area; utilizing a sensor to produce a signal indicative of astrength of the electromagnetic field and/or changes therein; marking atleast three anatomic locations on the subject's torso utilizing astylus; utilizing processing circuitry to: calculate an orientation ofthe subject relative to the electromagnetic field, based on the threeanatomic locations marked by the stylus, load a predefined anatomicalmap representing a torso; align the map, based on positionscorresponding to two locations on the subject's upper body derived fromthe at least three anatomic locations marked by the stylus; inserting agastroenteral tube into the patient; and showing on the map a path ofthe gastroenteral tube insertion; wherein the path is generatedaccording to changes in the signal produced by the sensor during theinsertion of the gastroenteral tube.
 11. The method of claim 10, whereinthe derived locations are the suprasternal notch and the xiphoidprocess.
 12. The method of claim 10, wherein said at least threeanatomic locations marked by the stylus comprise the xiphoid process andthe left and right claviculae.
 13. The method of 12, whereindetermining/estimating the orientation of the subject comprises defininga first vector between the xiphoid process and the left clavicula and asecond vector between the xiphoid process and the right clavicula. 14.The method of claim 13, wherein the position of the suprasternal notchis calculated based on the marked left and right claviculae.
 15. Themethod of claim 11, wherein the stylus is configured to mark at leastfour anatomic location, wherein the fourth anatomic location comprisesthe patient's suprasternal notch.